1. Field of the Invention
The invention relates to rotational hinge mechanisms for an illumination device, and more specifically, to a rotational hinge that allows a power cable of the illumination device to enter and exit through a rotational axis of the hinge. In addition, the rotational hinge described herein to allows the illumination device to be adjusted about the rotational axis and secured in a desired rotational position without the use of special tools or an additional locking mechanism.
2. Description of Related Art
Illumination devices using light emitting diodes (LEDs) provide many advantages over traditional light sources, such as fluorescent lamps and incandescent bulbs. These advantages include high energy conversion and optical efficiency, robustness, lower operating costs, small size and others. LED illumination devices generally include a plurality of LEDs of the same color, or a number of different colors. Multi-color linear LED lights often comprise red, green, and blue LEDs; however, some products use some combination of red, green, blue, white, and amber LEDs.
LED illumination devices (also referred to herein as light fixtures, luminaires or lamps) have been commercially available for many years in a number of different form factors (e.g., PAR, linear, A19, strip, automotive headlights, decorative, etc.). Parabolic light fixtures are often used as flood lights for interior or exterior applications. Typical applications for linear light fixtures include wall washing in which a chain of lights attempt to uniformly illuminate a large portion of a wall, and cove lighting in which a chain of lights typically illuminates a large portion of a ceiling.
Linear light fixtures generally include a number of LEDs arranged in a line in an elongated emitter housing. As with other form factors, power converters and drive circuitry are provided to power and control the light output from the LEDs. Unlike some form factors, linear light fixtures may be provided with a hinge that allows the fixture to rotate relative to a mounting bracket securing the fixture to a wall or ceiling.
One major design requirement for linear lighting fixtures is to have the power cable enter and exit through the axis of rotation. This requirement allows multiple fixtures to be chained together, and adjacent lighting fixtures to be independently adjusted, while maintaining a constant distance between connection points of adjacent lighting fixtures. However, this requirement complicates the design of the rotational hinges used in the linear lighting fixtures, as it prevents the hinges from both rotating and passing power through the same central axis. Therefore, conventional linear lighting fixtures tend to ignore this requirement and typically route the power cable through the fixture somewhere off the central axis. However, this inevitably produces strain between adjacent fixtures that are adjusted to different angles.
Another design requirement is to provide some means for adjusting and securing the light fixture in a desired rotational position. Most conventional linear light fixtures require special tools and/or an independent locking mechanism for adjusting and securing the light fixture. This is both cumbersome and time consuming, and can be frustrating if the tools are misplaced.
A need, therefore, exists for an improved rotational hinge for a linear light fixture, which allows a power cable to enter and exit through a rotational axis of the hinge, and which does not require special tools or an independent locking mechanism to secure the light fixture in place. Although an improved rotational hinge for a multi-color linear LED illumination device is disclosed herein, one skilled in the art would understand how the improved hinge design may be implemented in lighting fixtures having other form factors.